Advanced Materials Research Vols. 503-504

Abstract: poly-crystal nickel-titanium （NiTi ）has been a potential material,because of its good superelasticity, radiopacity and shape memory properties .To study further on this material (such as mechanical characteristic,elasticity), microcosmic properties of NiTi must be known. Therefore the crystal structure seems to be very significant for research.Traditional metallographical technology makes use of mechanical polishing and corrosion.In this work,a new method of electrochemical corrosion is put forward ,which is more easily and clearly to show the crystalline grain of metal

Abstract: This article develops one new test technology, dumbbell test method, for evaluation of the early age cracking property of Concrete Material under constraint conditions. Its exercise of stress risers could lead concrete to crack quickly, providing a quick method to evaluate the early age crack performance of concrete material and to perform simulated test at job site conveniently. By this method, the anti-cracking performance of different concrete material can be evaluated quickly in the construction site.

Abstract: The theoretical composition was made from MgO-rich MgAl2O4 (MR66) and alumina powder. The static crucible method was used to study alkali-resistance of the block samples. It has been observed that alkali steam permeated into the hole and reacted with corundum particles that produced β-Al2O3 by means of XRD, SEM and EDS. It led to volume expansion, cracks and melting erosion of corundum particles. The specimen of the 32% content of MgO has good physical and chemical properties and excellent alkali erosion performance. So the specimen is suitable for oxy-fuel combustion for glass melting furnace.

Abstract: In this article, morphology, IR and single fiber strength of cooling-mica fiber, and single yarn strength, yarn hairiness, twist, yarn evenness, resisting acid and alkali have been studied and tested.

Abstract: Unfired specimens were made with different aluninum content (0,2%,4%,6%,8%) respectively ,using high pure magnesia , magnesia-spinel and Aluninum as the main raw material. Unfired specimens were treated under the condition:110°C×24h drying,then 300°C×6h heating treatment.The properties and microstructure of the specimens were analyzed to investigate the reaction mechanism of these speciments and RH refinery slag.The result are shown that the addition of aluninum improves cold crushing strength of specimens,reaching to 63Mpa. The specimen with aluninum content of 8% shown the best slag resistance. The reaction mechanism between aluninum-magnesia-spinel complosite material and RH slag is different from magnesite-chrome brick. The major penetration element is Ca, and the Ca elment penetrated into the matrix reacts with corundum turning out a CA2 protective layer which can stop penetrating of slag.

Abstract: The combustion mechanism, which consisting of 22 species and 23 reaction equations, and three discrete models such as inertia, combusting, modification droplet, are employed for the investigation of gas-solid combustion in magnesium-aluminum based propellant ducted rocket based on thermal performance calculation. And path lines, temperature distribution, sediments are discussed after the computing method is validated by direct-connect experimentation and the flow field information, which obtained by numerical method and coincided with currently conclusions. The results indicated that the proposed method is reliable and practicable.

Abstract: CaCO3 whiskers were treated by stearic acid and the surface property of the treated whisker were evaluated by activation index. When the mass fraction of stearic acid was 4.0%, activation exponential increased to 80.0% almost from zero. The composites were prepared by blending with polypropylene and the treated whiskers. The performance of the composites, such as thermal behavior, mechanical properties and microstructure, were analyzed with differential scanning calorimetry, scanning electron microscopy and tensile testing. The results showed that CaCO3 whisker played heterogeneous nucleation to induce crystalline behavior of PP phase in the blends and the crystallization rate of PP phase also increased because of CaCO3 whiskers intervening. Moreover thermo-decomposing temperature and tensile strengths of the blends all increased with increasing whisker content, except a little less than that of pure PP as filling 3.22% CaCO3 whiskers, but the elongation at break increased with increasing whisker content.

Abstract: Based on the main features of coolsmart fiber and the theory of knitted fabric structures， two structures of sports and leisure knitted fabrics with fast moisture absorption, description and anti-bacterial function are introduced in this article, detailing the selection of raw materials, pattern formation effect, the machine code organization and cam set out.

Abstract: In the paper, titanium tri-aluminide (Al₃Ti) particles reinforced aluminium (Al)-based composite coatings were fabricated by infiltration plus in-situ techniques at 891.3 °C. The obtained composite coatings are characterized by XRD, SEM and friction and wear testers. The experimental results show that the reaction between Ti wires and Al molten increases with extending time, Ti wires can totally transform into Al3Ti particles for 20 min, which present blocky and strip-like states, respectively. The wear rates of the composite coatings decrease with increasing time.

Abstract: For researching the thermoelectric properties, bulk NiSb2 and the composite of CoSb3 and NiSb2 were prepared by sintering. The phases of samples were analyzed by X-ray diffraction and their thermoelectric properties were tested by electric constant instrument and laser thermal constant instrument. Experimental results show that, Bulk NiSb2 and the composite of NiSb2:CoSb3=2:8 and 4:6 were prepared by sintering at 600°C for 10min and they are N-type semiconductor materials with high densities of 6.998~7.142g/cm3. The bulk NiSb2 sample sintered is nearly single phase NiSb2, while the major phases of the composite of NiSb2:CoSb3=2:8 are major phase CoSb3 with impurity phase NiSb2. The electric resistivity of bulk NiSb2 sample increases with temperature rising while those of the composites (NiSb2:CoSb3=2:8 and 4:6) increase at 400~500 °C. The absolute values of Seebeck coefficients of the composite samples (NiSb2:CoSb3=2:8 and 4:6) increase with temperature rising and are evidently higher than those of bulk NiSb2. The power factors of the composites (NiSb2:CoSb3=2:8 and 4:6) are evidently higher than those of bulk NiSb2 while the power factor of NiSb2 sample varies not obviously with temperature rising, but those of the composites (NiSb2:CoSb3=2:8 and 4:6) increase with temperature rising and reaches the maximum value of 21.3 10-4Wk-2m-1 at 500 °C.